1. Technical Field of the Invention
The present invention relates to novel cosmetic compositions for topical application, for photoprotecting the skin and/or the hair against ultraviolet radiation (such compositions hereinafter simply designated "antisun," "sunscreen" or "photoprotective" compositions), and to the use of same for the cosmetic applications indicated above.
This invention more especially relates to the aforesaid sunscreen/cosmetic compositions comprising, formulated into a cosmetically acceptable vehicle, diluent or carrier therefor, a tripartite combination of (a) benzene-1,4-bis(3-methylidene-10-camphorsulfonic acid), optionally in partially or totally neutralized form, as a first screening agent, (b) at least one bisresorcinyltriazine compound as a second screening agent, and (c) as a third screening agent, at least one compound containing at least two benzazolyl groups or a compound containing at least one benzodiazolyl group, the said first, second and third screening agents being present in the subject compositions in proportions suitable for eliciting a synergistic effect with regard to the protection factors imparted.
2. Description of the Prior Art
It is known to this art that light radiation of wavelengths of from 280 nm to 400 nm promotes tanning of the human epidermis and that irradiation with wavelengths of from 280 to 320 nm, i.e., UV-B radiation, causes skin burns and erythema which may be harmful to the development of a natural tan; this UV-B radiation should thus be screened from the skin.
It is also known to this art that UV-A radiation, with wavelengths of from 320 to 400 nm, which causes tanning of the skin, also adversely affects it, in particular in the case of sensitive skin or of skin which is continually exposed to solar radiation. UV-A rays in particular cause a loss of skin elasticity and the appearance of wrinkles, resulting in premature aging. Such irradiation promotes triggering of the erythemal reaction or amplifies this reaction in certain individuals and may even be the cause of phototoxic or photoallergic reactions. It is thus desirable to also screen out UV-A radiation.
A wide variety of cosmetic compositions for photoprotecting (against UV-A and/or UV-B) the skin are known to this art.
These photoprotective/sunscreen compositions are typically emulsions of oil-in-water type (i.e., a cosmetically acceptable support (vehicle, diluent or carrier) comprising an aqueous dispersing continuous phase and an oily dispersed discontinuous phase) which contains, in various concentrations, one or more conventional lipophilic and/or hydrophilic organic screening agents capable of selectively absorbing harmful UV radiation, these screening agents (and the amounts thereof) being selected as a function of the desired protection factor (the protection factor (PF) being expressed mathematically by the ratio of the irradiation time required to attain the erythema-forming threshold with the UV screening agent to the time required to attain the erythema-forming threshold without a UV screening agent).